In typical eyeglass lens and frame design, each lens is generally round, generally rectangular, etc., edged to fit a specific frame shape. The lenses are fitted into a frame by a skilled optician, typically held in place using a small screw, a magnet, adhesive or mechanical locking. An end user, such as the eyeglass wearer cannot easily mount (or remount) lenses into the frame. Further, it is not typically possible, or at least practical, for an eyeglass wearer to switch the lenses with another pair of lenses, such as lenses of a different type, for example to switch to sunglass lenses from regular clear lenses. Additionally, after extended use, the frame, particularly a screw or other rigid lens retention mechanisms, may become loose, and there is a risk that the lens could be easily separated from the frame during wear of the eyeglasses.
For example, prior solutions for securing lenses in frames have included disposition of flanges at a lens edge, which are drilled to provide a (threaded) hole to receive a frame retention screw. However, as noted above with use, such screws can loosen, and/or the threads in the hole may strip, allowing the lens to be easily separated from the frame. Other solutions have called for the use of magnets fitted onto an edge of a lens and/or into a frame-defined slot to hold the lens into place. Another solution calls for use of mechanical rigid locks to index with a flange extending from the lens to hold the lens in place.